The invention relates to a reactor for the entrained-flow gasification of different solid and liquid fuels with an oxidizing agent containing free oxygen under normal or increased pressure up to 8 MPa. Here solid fuels are pulverized coal dust from coals of differing ranks, petrol cokes and other pulverizable solids having a calorific value exceeding 7 MJ/Nm3. Liquid fuels are oils or oil-solids or water-solids suspensions, such as coal-water slurries, for example. Autothermal entrained-flow gasification has been known for many years in gas generation technology using solid fuels. In this case the ratio of fuel to oxygenic gasification agent is chosen so that temperatures are obtained which are above the melting point of ash. The ash is then melted to a liquid slag which leaves the gasification chamber along with the producer gas or separately and is then directly or indirectly cooled. Such a device is disclosed in DE 197 181 317 A1.
A detailed description of one such gasification reactor fitted with a cooling screen can be found in J. Carl et al, NOELL CONVERSION PROCESS, EF-Verlag for Power and Environmental Engineering GmbH 1996, pages 32-33. In the design described there, a cooling screen consisting of gas-tight, welded cooling tubes is located inside a pressure vessel. This cooling screen is supported on a false bottom and can freely expand upwards. This ensures that the different temperatures due to start-up and shut-down processes and the resulting changes in length which occur, do not result in mechanical stresses which could possibly lead to destruction. In order to achieve this, there is no fixed connection at the upper end of the cooling screen, but a gap between the collar of the cooling screen and the burner flange, which ensures free movement. In order to prevent backflow in the cooling screen gap during pressure fluctuations in the producer gas system, the cooling screen gap is swept with a dry, condensate-free and oxygen-free gas. As practical experience shows, backflow with producer gas occurs in spite of sweeping—resulting in corrosion on the rear side of the cooling screen or on the pressure shell. This can lead to operational failures or even destruction of the cooling screen or pressure shell.